unbalanced impedance load

[The Vinyl Adventure]

a customer is intending on using a basic amp to drive 5 4ohm ceiling speakers in his shop
the amp is 8-16ohm handling
he wants to wire 3 speakers into one channel and 2 into the other. i have told him to wire in series giving 8ohm in one channel and 12 into the other - is this lack of balance between the 2 channels likely to cause problems?

i have told them it seems like a bad idea, but i would find out for sure
they have a 6th speaker, so with a bit of extra drilling could of course have 12 ohms into each channel, i guessed this would be the better way to go but they said it would be a lot of hassle to cut an extra hole in the cieling... shall i tell him to get out his drill?

[The Vinyl Adventure]

hello, anyone?

[Stratmangler]

Seems to me that he'd be better off running 100v line and going mono.

Chris:)

[Stratmangler]

An amp like this (http://www.studiospares.com/Power-Amplifiers/Inter-M-PA-935A-100V-Line-Amp/invt/427660) for starters, with these (http://www.cableuniverse.co.uk/catalog/quick-fit-ceiling-speaker-100v-line-6-quot-150mm-oslash.html) for speakers.

One single cable run from the amp, with the speakers connected up +ve to +ve, -ve to -ve (ie speakers chained together)

The speakers have selectable taps on the transformers so as long as you don't exceed the wattage of the amp you should have a very dependable (ie long lived) system.

Chris:)

[The Vinyl Adventure]

seems sencible, but in the mean while what is the best thing to do ... get him to wire in the 6th speaker?

[anthonyTD]

a customer is intending on using a basic amp to drive 5 4ohm ceiling speakers in his shop
the amp is 8-16ohm handling
he wants to wire 3 speakers into one channel and 2 into the other. i have told him to wire in series giving 8ohm in one channel and 12 into the other - is this lack of balance between the 2 channels likely to cause problems?

i have told them it seems like a bad idea, but i would find out for sure
they have a 6th speaker, so with a bit of extra drilling could of course have 12 ohms into each channel, i guessed this would be the better way to go but they said it would be a lot of hassle to cut an extra hole in the cieling... shall i tell him to get out his drill?
hi hamish,
if he wires them up as you have described it should be fine, he may get a slight volume diffrence between the one channel with the three on compared to the one with two, but so what, if their going into the ceiling then its not critical listening he's after is it!:):lolsign:
A...

[Stratmangler]

Tell him that his cash and carry system isn't up to the job;)

Whatever it is that he's got it is not up to the job in hand. It'll be broken before you know it, and it'll be your fault because you advised him.

Tell him the bit about a PRS license that he needs to play copyrighted material (and that includes radio). You'll get a blank look on that one !

Steer clear is my advice to you Hamish.

Chris:)

[Stratmangler]

Not preaching with my last post BTW - just been there, seen it, done it, got the T shirt etc...........

Chris:)

[The Vinyl Adventure]

... he knows about prs etc he has a sticker in the window... as for the rest of it, well its my job as long as im here so, well, i guess i will have to live with the concequences if it breaks.. we only sold him the skytronic speakers anyway and they arnt the bit thats likely to break... i did originally tell him a few months back that he needed some kinda pa gear idealy.. but he didnt listen!


anthony, cheers
they are wiering the 6th speaker in now just to be safe so all should be good ... provided he did actually understand what i meant wehn i said serial!

[Stratmangler]

Are these (http://www.prosound-dj.com/skytronic-131cm-ceiling-speaker-952527-p-1728.html) the speakers you mentioned ?

I'm not sure if the crossovers are likely to cause any funnies impedence-wise, or whether series/parallel wiring rules go out of the window because of the crossovers. The amp might not be happy at all.

Chris:)

[The Vinyl Adventure]

http://avslgroup.com/product/100.031UK
nah its these i think

[anthonyTD]

all they will probably have is a cap going from + of bass driver to tweeter, if thats the case then shouldnt cause any aditional problems.
A...

[anthonyTD]

http://avslgroup.com/product/100.031UK
nah its these i think
they look like ordinary full range speakers hamish so should be fine.
A...

[DSJR]

The worst clients we had were hairdressers. They'd spend a fortune on poshing up their salons to the latest "on trend" style and have peanuts for a sound system. they'd buy an "Argos Special" and come in crying to us when it didn't work. We found it almost impossible to get them to commit to a "proper" small-pa style system for all day music...

[The Vinyl Adventure]

Dave, you dunno how funny that is! I was telling the opticians (who bought the speakers in question) about some customers who own a new hairdressers (referbed from an old one). They still haven't come back to us about a pa setup for thier shop after I went and had a look at the current one.
It consisted of an old marantz amp with a iPod plugged into it! The amp kept on cutting out if it was turned up past 10 o'clock (signifyed a tipex mark) it turned out they had a string of speakers connected in the most haphazard way with various bits of wire shoved into the back. Some bell wire, some mains cable, 2 bits in one channel 3 in the other. They were convinced I could just swop the amp over and all would be good, I said I would go down and have a look. When I expalined it was the wiring at fault they asked me to re do it. The amp was on the second floor, they wanted the new one on the ground floor, there were three different types of speakers ... I ended up telling them I wasn't insured to carry out such work but I would help a spark if they bought all matching speakers... I guess they are wither struggling with the old amp still or found someone who just agreed with them instead of suggesting what was actually required